DENVER — More than 100 million American adults are single, and science knows almost nothing about them, said one psychology researcher.

The science of singles is sorely lacking, said Bella DePaulo, author of "Singled Out: How Singles Are Stereotyped, Stigmatized and Ignored, and Still Live Happily Ever After" (St. Martin's Griffin, 2007). All those studies finding that married people are happier and healthier? They suffer from the fatal flaw of comparing two groups that may have been quite different before the decision on whether to tie the knot, he said. And they put singles at an unfair disadvantage by lumping in never-married people with people made single by divorce and widowhood.

"There are so many false beliefs out there about single people and single life," DePaulo told Live Science ahead of a talk today (Aug. 5) at the annual meeting of the American Psychological Association in Denver. And those false beliefs are "sometimes presented as being based in research." [I Don't: 5 Myths About Marriage]

Singlehood in America

There are around 107 million single people over the age of 18 in the United States, including 93 million who aren't cohabitating, DePaulo said. About 63 percent of those people have never been married before. The never-married group is rising no matter how you slice it: A 2014 Pew Research Center study, for example, found that about 20 percent of adults over the age of 25 had never been married as of 2012, compared with only 9 percent in the same demographic in 1960. With marriage increasingly occurring later in life, people are spending more of their young adulthood single. U.S. Census data shows that the median age of first-time marriage is 29 for men and 27 for women. In 1960, the average woman was hitched by 20 and the average man by 23.

The cultural focus, DePaulo said, is still firmly on getting married. Everything from romantic comedies to government benefits urge walking the aisle. But economic opportunities for women and increased focus on forging individual paths to happiness means that there are more opportunities to stay single as a matter of choice, she said.

"We have to make space for the possibility that for some people, single life is their best life," she said.

The science of being single

This assertion seems to fly in the face of the bulk of the available psychology literature. Marriage, and long-term cohabitation, are associated with health benefits like survival after heart surgery and lower levels of stress and depression.

The problem is that studies that compare married and nonmarried people can't randomly assign people to get hitched or stay single; it's entirely possible that the sort of person who gets married is just different from the sort of person who doesn't. Another problem, DePaulo said, is that studies usually compare currently married people to currently single people. But those currently single people could have been previously married and divorced or widowed. Someone who is widowed might be very different from someone who is divorce, and both might be quite different from those who had never married. Nevertheless, the research lumps all these groups into the umbrella as "single."

A few studies that follow the same people over time find that when people go from unmarried to married or cohabitating, they see a slight uptick in happiness — but this honeymoon effect soon fades. These people may also get a health boost, possibly linked to marriage benefits like getting on a spouse's health care plan, a 2012 study found. That same study also found, however, that singles who get married lose contact with outside family and friends, an insularity effect seen in multiple studies, DePaulo said. In contrast, single people keep up more diverse social ties, she said. [7 Things That Will Make You Happy]

"It seems to be the single people who, in important ways, are holding us together," she said. Singles also volunteer more, and single children are more likely than married children to take care of their aging parents, she said.

DePaulo is now interested in studying the "single at heart," a group of people who are happily and voluntarily single. She's developing a psychological scale to identify people who feel this way. Preliminary research suggests that there are some serious benefits to singlehood. For example, people who score high on the desire to spend time alone are less likely to be neurotic and more likely to be open-minded than are people who prefer to be surrounded with others. Single people also develop a diverse portfolio of skills — they can't depend on a partner to do the taxes or cook dinner — which may give them a sense of mastery over life, DePaulo said.

"What I think we really need to do is find out much more about what's important to single people, what their lives are like, what they value — and that gives us a much fuller and fairer picture of the different ways of living a life," she said.

Original article on Live Science.

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